BEN3/BIG2 ARF GEF is Involved in Brefeldin A-Sensitive Trafficking at the trans-Golgi Network/Early Endosome in Arabidopsis thaliana
BEN3/BIG2 ARF GEF is Involved in Brefeldin A-Sensitive Trafficking at the trans-Golgi Network/Early Endosome in Arabidopsis thaliana
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DOI：
10.1093/pcp/pcx118
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发表时间：
2017-10-01
影响因子：
4.9
通讯作者：
Tanaka, Hirokazu
中科院分区：
文献类型：
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作者：
Kitakura, Saeko;Adamowski, Maciek;Tanaka, Hirokazu
跨高尔基体网络（trans-Golgi network，TGN）的膜运输对于正确地将各种膜蛋白分配到它们的目的地至关重要。极性定位的生长素外排蛋白，包括PIN-FORMED 1（PIN 1），在植物细胞中动态地在内体和质膜（PM）之间运输。PIN 1蛋白的细胞内运输对真菌毒素布雷菲德菌素A（BFA）敏感，已知其抑制鸟嘌呤核苷酸交换因子用于ADP核糖基化因子（ARF GEF），如GNOME。然而，BFA敏感的运输途径的分子细节尚未完全揭示。在以前的研究中，我们确定了一个拟南芥突变体BFA可视化内吞运输缺陷3（ben 3），表现出减少的敏感性，以BFA在BFA诱导的细胞内PIN 1凝聚。在这里，我们发现BEN 3编码BIG家族ARF GEFs的一个成员，BIG 2。用荧光蛋白标记的BEN 3/BIG 2与TGN/早期内体（EE）的标记物共定位。条件诱导的从头合成的PIN 1的检查证实，其分泌到PM是BFA敏感的，并建立BEN 3/BIG 2作为这种BFA作用在TGN/EE. further水平的关键组成部分，ben 3突变减轻BFA诱导的另一个TGN定位的ARF GEF，BEN 1/MIN 7的聚集。综上所述，我们的研究结果表明，BEN 3/BIG 2是一个ARF GEF组件，它赋予BFA敏感性的TGN/EE在拟南芥。
Membrane traffic at the trans-Golgi network (TGN) is crucial for correctly distributing various membrane proteins to their destination. Polarly localized auxin efflux proteins, including PIN-FORMED1 (PIN1), are dynamically transported between the endosomes and the plasma membrane (PM) in the plant cells. The intracellular trafficking of PIN1 protein is sensitive to the fungal toxin brefeldin A (BFA), which is known to inhibit guanine nucleotide exchange factors for ADP ribosylation factors (ARF GEFs) such as GNOM. However, the molecular details of the BFA-sensitive trafficking pathway have not been fully revealed. In a previous study, we identified an Arabidopsis mutant BFA-visualized endocytic trafficking defective 3 (ben3) which exhibited reduced sensitivity to BFA in terms of BFA-induced intracellular PIN1 agglomeration. Here, we show that BEN3 encodes a member of BIG family ARF GEFs, BIG2. BEN3/BIG2 tagged with fluorescent proteins co-localized with markers for the TGN/early endosome (EE). Inspection of conditionally induced de novo synthesized PIN1 confirmed that its secretion to the PM is BFA sensitive, and established BEN3/BIG2 as a crucial component of this BFA action at the level of the TGN/EE. Furthermore, ben3 mutation alleviated BFA-induced agglomeration of another TGN-localized ARF GEF, BEN1/MIN7. Taken together, our results suggest that BEN3/BIG2 is an ARF GEF component, which confers BFA sensitivity to the TGN/EE in Arabidopsis.